Crosstalk verifying device

Abstract

A node and coupling capacity selecting portion 4 extracts nodes (NDI) which simultaneously change from a net list (NTL) of a circuit diagram based on an input pattern (IP) and extracts a coupling capacity (CCI) not less than a designated value, and determines a node whose coupling capacity should be considered from the extraction result, and creats and holds information (ND/CC) of the judged nodes and the coupling capacities thereof. Then, simulation of the selected nodes including the coupling capacities thereof is conducted so that the result of the simulation is displayed in a waveform to thereby enable an efficient and highly precise crosstalk verification.

What is claimed is:  
     
         1 . A crosstalk verifying device for verifying a crosstalk influence of a coupling capacity parasitic in a circuit comprising: 
 node and coupling capacity selecting means for automatically selecting nodes and coupling capacities each having a crosstalk influence on a circuit operation to be considered, from a net list and layout data obtained from a circuit diagram, based on an input circuit operation pattern,    wherein the node and coupling capacity selecting means extracts nodes satisfying a predetermined node extraction condition, extracts coupling capacities satisfying a predetermined coupling capacity extraction condition, and determines and selects the nodes to be verified based on the extracted nodes and the extracted coupling capacities.    
     
     
         2 . The crosstalk verifying device according to  claim 1 , wherein the node and coupling capacity selecting means comprises: 
 node extracting means for extracting the nodes satisfying the predetermined node extraction condition from the net list based on the input circuit operation pattern; and    coupling capacity extracting means for extracting the coupling capacities satisfying the predetermined coupling capacity extraction condition from the layout data,    wherein the node extracting means extracts the nodes each of which is simultaneously changing as satisfying the predetermined node extraction condition, and    the coupling capacity extracting means extracts the coupling capacities each of which is not less than a designated value as satisfying the predetermined coupling capacity extraction condition.    
     
     
         3 . The crosstalk verifying device according to  claim 2 , wherein the node and coupling capacity selecting means further comprises selection node judging means for selecting and determining nodes whose coupling capacity should be considered based on the extraction results of the node extraction means and the coupling capacity extracting means, and creating and holding information of the selected nodes and the coupling capacities to be considered.  
     
     
         4 . The crosstalk verifying device according to  claim 1 , further comprising means for conducting simulation of the nodes including the coupling capacities thereof selected by the node and coupling capacity selecting means, and means for displaying waveform data obtained as the result of the simulation.  
     
     
         5 . The crosstalk verifying device according to  claim 1 , wherein the coupling capacity extraction condition is such that a ratio of a coupling capacity value with respect to the total capacity value of each node is not less than a designated ratio.  
     
     
         6 . The crosstalk verifying device according to  claim 1 , wherein the coupling capacity extraction condition is such that a coupling capacity value is not less than a designated value and a ratio of a coupling capacity value with respect to the total capacity value of each node is not less than a designated ratio.  
     
     
         7 . The crosstalk verifying device according to  claim 1 , wherein the node and coupling capacity selecting means comprises static crosstalk analyzing means for extracting the coupling capacities of all the nodes satisfying the predetermined extraction condition from the layout data, and conducting a static crosstalk analysis using the extracted coupling capacities and the net list.  
     
     
         8 . The crosstalk verifying device according to  claim 7 , wherein the static crosstalk analyzing means extracts a coupling capacity not less than a designated value as the coupling capacity extraction condition.  
     
     
         9 . The crosstalk verifying device according to  claim 7 , wherein the static crosstalk analyzing means extracts a coupling capacity when satisfying the coupling capacity extraction condition that a ratio of the coupling capacity value with respect to the total capacity value of each node is not less than the designated ratio.  
     
     
         10 . The crosstalk verifying device according to  claim 7 , wherein the static crosstalk analyzing means extracts a coupling capacity not less than a designated value and having a ratio of the coupling capacity value with respect to the total capacity value of each node not less than a designated ratio, as the coupling capacity extraction condition.  
     
     
         11 . The crosstalk verifying device according to  claim 1 , wherein the predetermined node extraction condition is such that a node is extracted which changes at a rate not less than a designated change rate.  
     
     
         12 . The crosstalk verifying device according to  claim 1 , wherein the predetermined node extraction condition is such that the nodes are extracted which simultaneously change and which change at a rate not less than a designated change rate.  
     
     
         13 . The crosstalk verifying device according to  claim 1 , further comprising list generating means for generating a list of the nodes and coupling capacities thereof selected by the node and coupling capacity selecting means.  
     
     
         14 . The crosstalk verifying device according to  claim 13 , wherein the list generating means generates the list of the nodes and coupling capacities thereof by classifying the nodes and coupling capacities into two groups: one group in which a delay of each node is slowed down under the influence of the coupling capacity and the other group in which a delay of each node is fastened under the influence thereof.  
     
     
         15 . The crosstalk verifying device according to  claim 1 , further comprising means for returning the coupling capacities of the nodes selected by the node and coupling capacity selecting means to the circuit diagram.  
     
     
         16 . The crosstalk verifying device according to  claim 1 , further comprising means for displaying the execution result of the simulation on the circuit diagram in a highlight manner.  
     
     
         17 . The crosstalk verifying device according  claim 1 , wherein the net list obtained from the circuit diagram is created as a net list including a parasitic resistance and a parasitic capacity of a wiring from the circuit diagram data and the layout data.